Described below are a method for controlling the run of technology specific Push Button Configuration sessions within a heterogeneous network with multiple communication network technologies, a registrar network node device for controlling the run of technology specific Push Button Configuration sessions within a heterogeneous network with multiple communication network technologies, a computer readable storage media executable by a processor for controlling the run of technology specific Push Button Configuration sessions within a heterogeneous network with multiple communication network technologies and a heterogeneous network for controlling the run of technology specific Push Button Configuration sessions.
The current data-centric use of networks (Internet access, media streaming) is increasingly extended towards home control functionality (home automation for climate control, lighting, burglar alarm, home energy network). Such home networks use according to FIG. 1 for instance various communication network technologies like Ethernet (IEEE 802.3), WLAN/WiFi (IEEE 802.11), and Power Line Communication (PLC; IEEE 1901). For this reason they are heterogeneous. The standard IEEE P1905.1, which according to D02 Draft Standard for Convergent Digital Home Network (CDHN) for Heterogeneous Technologies from Dec. 14, 2011 (described in IEEE P1905.1/D02 Draft Standard for Convergent Digital Home Network for Heterogeneous Technologies, IEEE P1905.1 document 1905_1-11-0101-02) is currently under development, defines a home network standard supporting different network technologies by a specified “IEEE P1905.1”-Abstraction Layer.
FIG. 2 shows the design of the abstraction layer based on the ISO/OSI-Reference Model with a management and data plane. The abstraction layer is embedded in an IEEE P1905.1-Architecture above a Media Access Control (MAC)-layer and a Physical layer as part of a “Network Node Device” NND within the heterogeneous network. Thus, the network node device NND uses the cited technologies like Ethernet (IEEE 802.3), WLAN/WiFi (IEEE 802.11), and Power Line Communication (PLC; IEEE 1901) and additionally a technology according to the specification of the Multimedia over Coax Alliance (MoCA) via corresponding interfaces according to FIG. 2. It is not compulsory or mandatory for a typical network node device to support all cited communication technologies. It is possible that the network node device NND supports only one or two of the cited technologies or completely other network technologies. Thus the network node device NND supports at least one network technology.
At least one goal of the IEEE P1905.1 standardization activities is the security mechanism during a setup or registration of a new device, called an “enrollee”, which wants to join the heterogeneous network. The security mechanism is needed to protect the home network from external attacks. Such security mechanisms have to be configured with a security credential (password, passphrase, cryptographic key) that is burdensome to set-up manually.
The specific problem of using a Push-Button Configuration (PBC) in an “IEEE P1905.1”-network comes from the fact that multiple devices (belonging even to different technologies) are activated to accept a new device. So in the current version of the standard, more than one device could register with the “IEEE P1905.1”-network after a single button press. An attacker node may therefore register undetected when an authorized registration of a new device takes place. Further, even in a scenario where there is no attacker node, if multiple existing nodes of the home network (for e.g. access points) activate their technology specific PBC mode simultaneously it may lead to failure of the new node's attempts to join the network. This is specifically the case when the access points (or the nodes involved in registering the new node in the network via the technology specific Push Button Configuration) are IEEE 802.11 (WLAN) access points supporting as a Push-Button Configuration in the WLAN environment a Wi-Fi Protected Setup (WPS). Taking this into account a technology specific Push Button Configuration is a Push Button Configuration, which is used specifically for each of the communication network technologies within the heterogeneous network.
Currently a push button method is provided in heterogeneous convergent digital home networks in order to allow the end-user to easily setup the security credentials and permit new network devices to join the convergent digital home network. An example for this is the mechanism provided in the IEEE P1905.1 draft standard under development. Here using the P1905.1 push button mechanism, technology specific Push Button Configurations (PBC) are activated on authenticated devices in the home network. This enables the new joining device to carry out a technology specific Push Button Configuration itself with a suitable device (based on range, connectivity, and media type) to get security credentials to join the home network.
One of the basic problems with this is, that multiple technology specific Push Button Configurations (PBC) triggered by the same push button event may actually fail because they recognize each other as a conflicting PBC run. This is especially the case in Wi-Fi Protected Setup (WPS) with “Wi-Fi”-devices.
The mechanisms provided however are limited, for example, they do not work for the case of home networks where multiple registrars are present [multiple registrars are possible, see page 11 of the “Wi-Fi Protected Setup (WPS)” Specification defined by the Wi-Fi Alliance Version 1.0, September 2006, which is the de-facto standard for WLAN security setup (see en.wikipedia.org/wiki/Wi-Fi_Protected_Setup and www.wi-fi.org/wifi-protected-setup).
Furthermore in the IEEE P1905.1 solution the technology specific Push-Button Configuration is started only by the registrar, which implies that for the case where the new device is not within range of the registrar, but within the range of another “Wi-Fi”-access point the Push-Button Configuration attempt fails.
Additionally, the registrar is a logical entity and can be separated from the access points. In this case the registrar itself might not have the capability to start a “Wi-Fi” specific Push Button Configuration at all. This will prevent any nodes from joining the network using the “Wi-Fi” technology specific PBC.
Convergent Digital Home Networks (CDHNs) are home networks where different heterogeneous communication technologies are converged in a single home network. This is done by introducing an abstraction layer above the different communication technologies. The goal is a common user view and user experience independent of the underlying communication technology.
Such a Convergent Digital Home Network is being defined, for instance, in the IEEE P1905.1 working group. The IEEE P1905.1 standard which is currently being defined specifies an abstraction layer, which converges IEEE 802.3, IEEE 802.11, IEEE 1901 (PLC), and Multimedia over Coax Alliance (MoCA®) and is extensible to other communication technologies.
Push Button Configuration is an accepted technique for user-friendly security setup in home networks. In a Convergent Digital Home Network, the push button configuration has to be agnostic to the underlying communication technologies.
The idea is that the user presses a push button on any of the network devices (the network Push Button Event (NW-PBE)) and on the new device, the enrollee (the enrollee Push Button Event (E-PBE)). This will start the push button configuration, even in the case where the network node with the NW-PBE and the enrollee have no communication technology in common, that is, they communicate through intermediate network nodes of the Convergent Digital Home Network. Changes to the technology-specific PBC method are considered to be too expensive and are not backward compatible.
Several communication technologies provide a technology-specific Push Button Configuration method (ts-PBC method). Such a method can be triggered by the abstraction layer of the Convergent Digital Home Network, but the ts-PBC is solely controlled by the rules of the specific communication technology. That is, the Convergent Digital Home Network can not influence the ts-PBC run except for starting it.
The problem of “overlapping PBC sessions” is, that more than one device (enrollee) wants to join the network for a single push button event. It can be assumed that one of the devices is an attacker. The problem of overlapping PBC sessions is according to FIG. 3 more severe in Convergent Digital Home Networks due to the potential multi-hop nature and the different communication technologies:                The overlapping PBC sessions might happen with different technologies, so that technology-specific mechanisms for the detection of overlapping PBC sessions will not work.        The geographic distance between the overlapping PBC sessions can be larger compared to ts-PBC sessions due to the multi-hop capability of the Convergent Digital Home Network. In a specific technology, the Push Button Configuration is usually focused on a single network device such as a Wi-Fi Access Point. In a Convergent Digital Home Network, the Push Button Configuration can happen at any network node with a ts-PBC method.        
The “deadlock of technology specific PBC sessions” is a new problem that occurs in Convergent Digital Home Networks. If the Convergent Digital Home Network starts multiple ts-PBC sessions of the same communication technology due to the propagation of the NW-PBE to all Convergent Digital Home Network nodes, each ts-PBC session will detect each other as an overlapping session and will cancel the Push Button Configuration runs, so that no Push Button Configuration will happen for this communication technology at all.
Particularly, this is a problem of Wi-Fi Protected Setup, the PBC method for IEEE 802.11/Wi-Fi (cf. FIG. 3).
The current version of the draft IEEE P1905.1 specification does not define a mechanism for preventing or detecting overlapping sessions in the increased scope of this problem in Convergent Digital Home Networks.
IEEE P1905.1 submission 11/0087r1 (see [Parag Mogre, Michael Bahr: Security Improvements for P1905.1, IEEE P1905.1 document 1905_1-11-0087-01) defines a similar method that detects and prevents overlapping sessions in a Convergent Digital Home Network, but it requires some interaction with the technology-specific PBC method. The CDHN node detects an enrollee solely based on the received technology-specific PBC messages sent by the enrollee; and in case of overlapping PBC sessions a PBC Abort message stops ongoing ts-PBC runs.
Furthermore, such a functionality as a CDHN registrar is not known and some parts of the description are rather high level.
IEEE P1905.1 submission 12/007r1 (see Parag Mogre, Michael Bahr: Push Button, IEEE P1905.1 document 1905_1-12-0007-01) describes a scheme rudimentarily that at least detects overlapping PBC sessions, but cannot prevent them. The CDHN nodes are informed about successful Push Button Configurations.
The current version of the draft IEEE P1905.1 specification does define a method targeted at the problem of deadlock of ts-PBC sessions for the case of Wi-Fi Protected Setup. Only the Access Point (AP) where the NW-PBE occurred (push button pressed) or the Wi-Fi registrar can start the WPS push button method. The short-coming of this method is that an enrollee will never be able to connect to the network if it is only in range of an access point that will not be allowed to enable the WPS Push Button Configuration.
IEEE P1905.1 submission 12/007r1 describes an alternative scheme for the problem of deadlock of Wi-Fi Protected Setup PBC sessions. Here, only the AP where the NW-PBE occurred (push button pressed) is activated or all access points are activated with a random delay. This means, that all access points start their WPS PBC at different times thereby reducing the chance of deadlock due to technology-specific overlapping PBC sessions while connecting the enrollee at any access point of the Convergent Digital Home Network.
The most well-know technology-specific Push Button Configuration method is as indicated above the Wi-Fi Protected Setup (WPS) described in Wi-Fi Protected Setup Specification, Version 1.0, September 2006.
The method and network node device described below for controlling the run of technology specific Push Button Configuration sessions within a heterogeneous network with multiple communication network technologies as well as a heterogeneous network with multiple communication network technologies, is capable of achieving a reliable prevention of overlapping PBC sessions without any deadlocks of technology specific PBC methods.